Field of the Invention
The present invention is related to an immersion objective for a microscope optical system.
Description of the Related Art
In recent years, techniques of observing deep portions of a sample have developed remarkably in the field of microscopy, making it possible to entirely observe the inside of ever-larger samples. This has made it necessary for microscope optical systems to have immersion objectives with an ever-longer working distance and an excellent aberration performance over a wide field of view.
Immersion objectives with a wide field of view and a long working distance in conventional techniques are described in for example Japanese Laid-open Patent Publication No. 2015-079222 and Japanese Laid-open Patent Publication No. 2015-079144.